TWI Industrial Member Report Summary 464/1992
By T R Gurney
Background
In recent years a substantial number of fatigue tests have been carried out on as-welded joints under variable amplitude loading, most of the tests involving the peak stress range being either at R = 0 or
R = -1. However, extremely few comparable tests have been carried out on stress relieved joints. The first objective of this work was therefore to obtain directly comparable results for as-welded and stress relieved joints for both stress ratios.
Also, in view of the doubt that exists as to whether tests on as-welded joints actually simulate the situation in real structures, with their (potentially) higher residual stresses, or whether such simulation is better achieved by testing under 'stalactitic' loading (i.e. pulsating downwards from a fixed peak tensile stress), some comparative tests have been made on as-welded joints both at R = 0 and under stalactitic loading. In order to enable a relatively high peak stress to be used, these specimens were fabricated from high tensile steel (RQT 700).